A touch panel is an input device allowing data to be input directly onto a display The touch panel is used by being placed on a front surface of a display. The touch panel can be used for various purposes because the touch panel data can be input based on data that is visually recognized from a display.
A known resistive film type touch panel has a transparent conductive film formed on an upper electrode substrate and a transparent conductive film formed on a lower electrode substrate in a manner that the conductive films face each other. By exerting force to the upper electrode substrate, the conductive films contact each other to enable detection of the position at which force is exerted.
The resistive film type touch panel can be categorized into a four-wire type and a five-wire type. The four-wire type touch panel has X-axis electrodes arranged on one of the upper and lower electrode substrates and Y-axis electrodes arranged on the other one of the upper and lower electrode substrates (See Patent Document 1).
The five-wire type touch panel includes an electrode substrate that has both X-axis electrodes and Y-axis electrodes provided thereon and another electrode substrate that is used as a probe for measuring potential (See Patent Document 2).
Patent Document 3, for example, discloses a four-wire type touch panel that can detect multiple touched areas.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-272722;    Patent Document 2: Japanese Laid-Open Patent Publication No. 2008-293129    Patent Document 3: Japanese Laid-Open Patent Publication No. 2009-176114
However, multi-touch cannot be easily detected with the five-wire type touch panel.